The International Space Station will be flying over the United States on Saturday evening, and unfortunately for people on Earth, it’s going to be doing so at a pretty good time to cause problems for traffic on the ground.
The station is scheduled to be passing over northern Europe and North America on Saturday at 6:17 p.m. E.T.
That’s bad news for Americans who want to watch an East Coast snowstorm or the Super Bowl. (It’ll be the highest orbit for the space station over land in more than six years.)
It’s also bad news for the million or so pieces of space junk that orbit Earth and are about a quarter-mile across, or five times larger than the space station itself. The space station is considered too big to reach with a typical car and clear of any debris, so it lands somewhere hard by the ocean without humans on board. (Smaller bits of debris are less dangerous.)
While the space station’s orbit is normally fairly uniform between 12,000 and 15,000 miles above Earth, it has an extremely narrow window of opportunity to pass over Earth. The space station can only make an annual pass over certain areas for about 28 hours each year. So to avoid a collision, there are only two or three times each year that the space station is within close proximity to a place on Earth where it can get a spectacular low flyby.
“The orbit of the ISS is exceptionally small and will never decay, ever,” NASA said in a March 4 post on its website. “By the time debris affects a spacecraft, it is long past the point at which the debris field can be effectively destroyed. The only way to prevent debris impact is to conduct routine disposal at the time of launch.”
Saturday’s track highlights just how close some of the smaller pieces of space junk can be to people on Earth. Most of the stuff in orbit comes from work like the Hubble Space Telescope and Mars orbiters. When these objects come back down to Earth and can’t reenter through the atmosphere intact, they crash into land and sea.
The majority of space junk affects other satellites or the International Space Station, but some things like the International Space Station are pretty large, visible and close to the ground. For instance, in 2016 a meteoroid hit the space station, but it’s unclear whether it caused any damage.